Modification of turbulent dissipation rates by a deep Southern Ocean eddy

Sheen, K. L. and Brearley, J. A. and Naveira Garabato, A. C. and Smeed, D. A. and St. Laurent, L. C. and Meredith, M. P. and Thurnherr, A. M. and Waterman, S. N.

abstract: The impact of a mesoscale eddy on the magnitude and spatial distribution of diapycnal ocean mixing is investigated using a set of hydrographic and microstructure measurements collected in the Southern Ocean. These data sampled a baroclinic, mid-depth eddy formed during the disintegration of a deep boundary current. Turbulent dissipation is suppressed within the eddy, but is elevated by up to an order of magnitude along the upper and lower eddy boundaries. A ray-tracing approximation is employed as a heuristic device to elucidate how the internal wave field evolves in the ambient velocity and stratification conditions accompanying the eddy. These calculations are consistent with the observations, suggesting reflection of internal wave energy from the eddy center and enhanced breaking through critical layer processes along the eddy boundaries. These results have important implications for understanding where and how internal wave energy is dissipated in the presence of energetic deep geostrophic flows. 
@article{Sheen-etal-2015,
  author = {Sheen, K.~L. and Brearley, J. A. and Naveira~Garabato, A. C. and Smeed, D. A. and St.~Laurent, L. C. and Meredith, M. P. and Thurnherr, A. M. and Waterman, S. N.},
  title = {Modification of turbulent dissipation rates by a deep {Southern} {Ocean} eddy},
  journal = {Geophys. Res. Lett.},
  year = {2015},
  pages = {3450--3457},
  volume = {42},
  issue = {9},
  doi = {10.1002/2015GL063216},
  url = {https://eprints.soton.ac.uk/376616/}
}


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